A total of approximately 1,000 acres were listed for sale in Mason County, Illinois, recently, representing a total value of almost $4 million in Mason County farmsand rural real estate for sale. Mason County ranks 90th out of 102 counties in the Prairie State for the total number of acres of land currently advertised for sale. Of all locations in Mason County with farms, rural land, hunting land and other land for sale, Manito featured the most land for sale. Mason County is Illinois's 47th largest county (563 square miles). It's located in the Western Illinois region of Illinois.